This application claims priority to French Patent Application No. 20120062429 filed 20 Dec. 2012, the entire contents of which are hereby incorporated by reference.
1. Field of the Invention
The present invention relates to a flight data recorder, more commonly called black box.
2. Discussion of Prior Art
With reference to FIG. 1, a flight data recorder 1 comprises a frame 2, a recorder 3 and a ULB beacon 4 (ULB standing for Underwater Locator Beacon). The recorder 3 is fixed to the frame 2 and the ULB beacon 4 is fixed to the recorder 3. The recorder 3 and the frame 2 both incorporate various electronic elements intended for the operation of the flight data recorder.
A flight data recorder is usually placed in the rear part of the fuselage of an aircraft because that is the part whose integrity is best retained when an aircraft impacts with the sea. A flight data recorder can, however, be separated from this part of the fuselage when the impact of the aircraft with the sea is violent, or when the aircraft fuselage is broken up before the latter impacts with the sea. In these cases, the search operations for the flight recorders are long and tedious because they entail first defining an approximate position of the rear part and searching a radius of several hundred meters around this approximate position.
The approximate position of the rear part is computed from uncertain parameters, such as the last assumed trajectory of the aircraft, the analysis of the underwater currents or the analysis of the drift of floating debris.
In order to speed up the search, all flight data recorders are colored orange or red, and fluorescent in the dark. Furthermore, the ULB beacon is triggered on immersion and emits an omnidirectional signal.
It will be understood that the computed approximate position of the rear part must be as close as possible to its real position because, on the one hand, the color of the flight data recorders may be difficult to see at a distance in great depths or when the water is disturbed and, on the other hand, the omnidirectional signal may be difficult to pick up when the underwater relief is steep. In the latter case, the detection of the signal is then possible only in an area close to the flight recorders.